This title was first published in 1967. In the foreword the author states that the present Essay was not written in haste, and probably cannot be read through in haste either. It is the result of my thinking about our society for the last sixteen years. The section "The Transition Period" was written and published as long ago as 1951 ; the last section, on the theory of the party, was written only after the Brioni Plenum of the Central Committee of the Communist Party of Yugoslavia, when study of these problems had become socially relevant, in the sense of the quotation of Marx that has been adopted as the epigraph of this book. Part of the text has been published in Ekonomist, Pregled, Gledüta and Na&e teme. Part I and Chapters 11 and 14 are taken from my book Towards a Theory of Planned Economy.